ICL 8.0: Anatomy of the Neck Flashcards
where is the hyoid bone located?
between the mandible and hyoid cartilage
many ligaments and muscles etc. attach to it!
what are the bony landmarks of the hyoid bone?
the whole bone is horseshoe shaped
there are 2 greater horns and 2 lesser horns –> the lesser horns stick up vertically
which cervical vertebrae are atypical?
C1
C2
C7
what are the characteristics of the atlas?
- no body; instead it has 2 lateral masses
the two lateral masses are connected together anteriorly by the anterior arch and posteriorly by the posterior arch
- no spinous process
- transverse formamen (vertebral artery passes through)
- transverse ligament that connected the lateral masses
what is the atlantooccipital joint?
the superior articular surface of the atlas articulates with the occipital condyles of the skull to form the atlantoocipital joint
this allows for flexion and extension aka the “yes” motion
what are the characteristics of the axis?
- dens/odontoid process
- it does have a body!
- bifurcated spinous process
- transverse foramen
what is the atlantoaxial joint?
there’s actually 3 atlantoaxial joints! two lateral and one median
the median atlantoaxial joint is where the dens articulates with the atlas and allows for your head to rotate and make the “no” motion
the lateral atlantoaxial joints are you normal facet joint
what is a C2 fracture?
Hangman’s fracture
usually due to hyperextension that leads to a pars interacticularis fracture
what are the characteristics of normal cervical vertebrae?
C3-C6 are typical cervical vertebrae
- body
- pedicles
- transverse processes with transverse foramen
the transverse processes are made up of the anterior and posterior tubercles
- inferior and superior articular processes
- uncinate process
what is special about the transverse process of C6?
the anterior tubercle of C6 is called carotid tubercle
the common carotid artery passes next to the carotid tubercle
so in patients with high blood pressure or HR, you can massage the carotid artery into the carotid tubercle to reduce HR and BP
what are the characteristics of C7?
- spinous process is NOT bifurcated = vertebra prominent
- NO anterior tubercle of the transverse process
patients who do have an anterior tubercle can develop thoracic outlet syndrome from the tubercle compressing on the lower trunk of the brachial plexus
what is the platysma?
a superficial muscle in the neck; like if you strain your neck that’s the muscle you’re seeing
it attaches proximally to the clavicle and distally to the mandible
what is the action and innervation of the platysma?
cervical branch of the facial nerve
it’s involved with making facial expressions
also people hypothesize that maybe when it contracts it prevents veins from collapsing by shielding them from negative pressure; total speculation
what do you need to be careful with when it comes to incisions involving the platysma?
during suturing skin incision or wounds in the neck, the cut platysma needs to be sutured separately to prevent gaping of the wound and stretching of the skin scar
what are the two main veins in the neck?
- external jugular vein
2. anterior jugular vein
what is the course of the external jugular vein?
it starts from the union of the posterior division of the retromandibular vein with the posterior auricular vein
it then drains into the subclavian vein
what is the course of the anterior jugular vein?
it starts by the confluence of submandibular and submental veins
it runs close to the midline of the neck on each side
the right and left anterior veins connect at their proximal ends via the jugular arch which then drains into the external jugular vein (which then drains into the subclavian vein)
what are engorged neck veins pathological for?
engorged neck veins are common signs for heart disease such as, right-sided heart failure, cardiac tamponade, tricuspid valve disease, pulmonary hypertension
during what procedure should you be worried about piercing the jugular arch?
tracheostomy
the jugular arch is in your way during tracheostomy and may cause bleeding
the jugular arch connects the left and right anterior jugular veins
what are the 4 cutaneous nerves of the neck? what are their nerve roots?
- great auricular (the biggest) (C2,C3)
- transverse cervical (C2, C3)
- lesser occipital (C2)
- supraclavicular (C3,C4)
what is a good location to perform cervical plexus nerve block?
the cutaneous branches of the cervical plexus outcrop at the middle of the posterior border of the sternocleidomastoid muscle
this means that the great auricular, lesser occipital, supraclavicular and transverse cervical nerves all come out at this spot to do their cutaneous innervation of the neck so it’s a great spot to do a cervical plexus nerve block since they’re all there!
inflammation of the gall bladder causes referred pain in the right shoulder? why?
the gall bladder and the cutaneous sensation of the right shoulder both have C3/C4 roots
so since the brain doesn’t really process visceral pain from organs such as the gallbladder, this pain is instead interpreted as right shoulder pain via the supraclavicular nerve
what are the borders of the anterior triangle of the neck?
Mid-line of the neck
Lower border of the body of the mandible
Anterior border of sternocleidomastoid
what are the borders of the posterior triangle of the neck?
posterior border of the SCM
middle 1/3 of the clavicle
anterior border of trapezius
what is the sternocleidomastoid origin, insertion, innervation?
there are two heads of the muscle:
the sternal head comes from the manubrium while the clavicular head comes from the medial 1/3 of the clavicle –> the depression between the two is know as lesser supraclavicular fossa which contains supraclavicular lymph node
they insert at the mastoid process and the lateral 1/3 of the superior nuchal line
they’re innervated by the spinal accessory nerve
what is the action of the sternocleidomastoid?
acting alone it tilts the head to ipsilateral shoulder but rotates the chin to the contralateral side
but acting together it extends and flexes the neck
what is Torticollis?
aka Wryneck
it’s a congenital or spasmodic contracture of the SCM that result in deformity of the head and neck
persistent spasmodic contraction of SCM my require division of spinal accessory nerve
what are Virchow lymph nodes?
between the sternal and clavicular heads of SCM there one/multiple lymph nodes and on the left side of the body they’re specifically called Virchow lymph nodes
they drain the abdominal structures and are enlarged in abdominal malignancy
on the right side of the body, these lymph nodes drain thoracic content structures and are enlarged in thoracic malignancy
what is the clinical significance of the lesser supraclavicular triangle?
it’s the opening between the clavicular and sternal head of the sternocleidomastoid
it’s where you can access external jugular vein for central lines!
what are the subdivisions of the anterior triangle?
- muscular triangle
- carotid triangle
- digastric triangle
- submental triangle
what are the borders of the muscular triangle?
anterior: mid-line of the neck
posterior: anterior border of SCM
superior: superior belly of omohyoid muscle
what are the contents of the muscular triangle?
- all the infra hyoid muscles!
sternohyoid, superior belly of the omohyoid, sternothyroid, and thyrohyoid
- viscera of the neck
larynx, pharynx, trachea, esophagus, thyroid and parathyroid gland
what are the infrahyoid muscles?
LAYER 1
1. omohyoid (superior and inferior belly)
- sternohyoid
SECOND LAYER
1. sternothyroid
- thyrohyoid
they all depress the hyoid bone
what is the innervation of the infrahyoid muscles?
they are all supplied by the ansa cervicalis
EXCEPT the thyrohyoid which is innervated by C1
what are the boundaries of the carotid triangle?
anterior: superior belly of Omohyoid
posterior: anterior border of SCM
superior: posterior belly of digastric
the floor of the carotid triangle is the superior and middle constrictor muscles of the pharynx
what are the contents of the carotid triangle?
- common, external and internal carotid arteries
- internal jugular vein
- the last 4 cranial nerves
- ansa cervicalis
- cervical sympathetic trunk
what are the last 4 cranial nerves?
- glossopharyngeal nerve
- vagus nerve
- spinal accessory nerve
- hypoglossal nerve
describe the common carotid artery in the carotid triangle
the right common carotid arises from the brachiocephalic trunk
the left common carotid arises from the arch of the aorta
the common carotid arteries then dilate at the distal ends to form the carotid sinus where it divides into two terminal branches; the external and internal carotid arteries at the upper border of thyroid cartilage
no other branches in the neck!!
where can you feel the common carotid artery pulse? why is this significant?
common carotid pulsation can be felt anterior to the anterior border of SCM and below the angle of the mandible
this is where you can listen for arterial bruit!!
what is hypersensitive carotid sinus syndrome?
the carotid sinus has baroreceptors that monitor BP
some individuals have hypersensitive carotid sinus in which sudden movements of the head or pressure over the carotid sinus may evoke vagal reflex of slowing the heart rate with concomitant drop in blood pressure which may make the individual faints
which receptors are in the carotid body?
chemoreceptors for O2 and CO2
if the level of CO2 and O2 changes, the phrenic and intercostal nerves are responsible for breathing and will change your breathing to bring gas levels back to normal
where does the external carotid artery start and end?
the external carotid artery is a branch of the common carotid artery
it starts at the carotid sinus as one of the two terminal branches of the common carotid (the other is the internal carotid artery)
it ends at the neck of the mandible by giving two terminal branches = the maxillary and superficial temporal arteries
what are the important branches of the external carotid artery?
- superior thyroid
- lingual
- facial
- occipital (pierces the trapezius)
the external carotid artery is more surgically accessible than some of it is deep branches
therefore, it is easier to ligate external carotid to control bleeding from one of its deep less accessible branches. It is ligated in the carotid triangle anterior to the anterior border of the sternocleidomastoid
where does the internal jugular vein start and end?
it starts at the jugular foramen in the skull as a continuation of sigmoid sinus
it ends behind the sternoclavicular joint by joining the subclavian vein to form the brachiocephalic vein
it drains the brain, head and neck
what should you be most scared of if the internal jugular vein is lacerated?
for most of its course, the IJV is protected by sternocleidomastoid
in the lower part between the sternal and costal head it is subcutaneous and may be punctured in a stab wound
bleeding may ensue, but the major risk is suction of air due to negative pressure, causing air embolism which may result in death (200-300 ml of air is fatal)
what is the internal jugular vein often used for?
the extremely constant position and big size makes it a good vein to insert a central venous catheter to administer long term medications
what neural structure is in the carotid triangle?
ansa cervicalis
this is part of the cervical plexus but it’s located in the carotid triangle just beneath sheath
it’s formed by C1, C2, and C3 which together form a loop that then branches to supply all the infrahyoid muscles (except the thyrohyoid which is C1)
what is the route of the vagus nerve?
it leaves the skull through the jugular formamen and runs in the carotid triangle inside the carotid sheath, posterior to the common carotid and internal jugular vein
it then leaves the neck through the superior thoracic aperture behind the sternoclavicular joint
what are the branches of the vagus nerve?
the superior laryngeal nerve comes off of the vagus nerve
it then branches into the internal and external laryngeal nerves
there’s also the recurrent laryngeal nerves which branch off of the vagus nerve either under the aorta on the left side or under the right subclavian artery on the subclavian
the right recurrent laryngeal nerve loops under the subclavian artery and goes back up between the esophagus and trachea to supply sensation to the muscles of the larynx
but on the left side, the left recurrent laryngeal nerve loops directly under the arch of the aorta
what is the route of the spinal accessory nerve 11?
it leaves the cranial cavity through the jugular foramen and runs in the carotid triangle for a short distance then dives into the sternocleidomastoid and supplies it
it then emerges from the posterior border of the SCM and runs in the posterior triangle of the neck
it then disappears under the deep surface of trapezius and ends by supplying it
which CN is the spinal accessory nerve?
11
which CN is the hypoglossal nerve?
12
what is the route of the hypoglossal nerve?
it emerges from the skull through the hypoglossal canal
it then runs in the carotid triangle downward, parallel to the posterior belly of the digastric muscle
then it passes under the intermediate tendon of the digastric muscle to reach the digastric triangle
then once it’s in the digastric triangle, it dives deep to the mylohyoid muscle to reach the oral cavity where it ends by supplying the muscles of the tongue
what is the route of the cervical sympathetic trunk?
runs in the carotid triangle outside the carotid sheath over the prevertebral fascia
it has 3 ganglia
what are the 3 ganglia of the cervical sympathetic trunk?
- superior cervical ganglion is the fused upper 4 cervical ganglion (C1-C4)
- middle cervical ganglia is the fused C5 and C6 cervical ganglia
- inferior (stellate) ganglion is the fused C7, C8 and T1 ganglia
if there’s a lesion on the cervical sympathetic trunk, what would happen?
a lesion of the cervical sympathetic trunk results in loss of sympathetic innervation to the head
this is a condition called Horner’s syndrome!
it’s characterisiteed by ptosis, myosis and anhidrosis
what are the boundaries of the digastric triangle?
the posterior digastric muscle to the lower border of the body of the mandible to the anterior belly of the digastric muscle
the floor is the mylohyoid muscle
what are the contents of the digastric triangle?
- submandibular salivary gland
- part of the hypoglossal nerve
- facial artery
what happens if there’s a tumor on the submandibular salivary gland?
it could compress the hypoglossal nerve
what are the 4 suprahyoid muscles?
- digastric (posterior and anterior belly)
- stylohyoid
- mylohyoid
- geniohyoid
describe the digastric muscle?
2 bellies = posterior and anterior
the two bellies have intermediate tendon between them and is kept in place by fibrous loop attached to the hyoid bone
what is the innervation of the digastric muscle?
anterior belly = nerve to mylohyoid
posterior belly = facial
what are the subdivisions of the posterior triangle of the neck?
- occipital triangle
- supraclavicular triangle
the inferior belly of omohyoid divides the posterior triangle into supraclavicular below and occipital triangle above.
what are the contents of the posterior triangle of the neck?
- branches of the cervical plexus
- spinal accessory nerve
- terminal part of external jugular vein
- occipital artery (at the apex)
- transverse cervical artery
- suprascapular artery
- dorsal scapular artery
- inferior belly of omohyoid
- subclavian artery
- subclavian vein
slide 35 GO LOOK
which muscles form the floor of the posterior triangle of the neck?
- anterior scalene
- middle scalene
- posterior scalene (not exactly in the floor because it’s deep)
- levator scapulae
- splenius capitis
- semispinalis capitis
what emerges between the anterior and middle scalene?
brachial plexus
which nerve roots form the cervical plexus?
the anterior rami of the first 4 cervical
each ramus (except the first) divides into ascending and descending parts forming communicating loops –> from these loops arise the motor and cutaneous branches
what are the motor roots of the phrenic nerve?
C3, C4, C5 keep the diaphragm alive
why is the spinal accessory nerve susceptible to damage?
the superficial position of the spinal accessory nerve in the posterior triangle just beneath the skin and investing layer of the deep facia makes it susceptible to injury during surgery and stab wound
what is the effect of injury of spinal accessory nerve in the posterior triangle?
shoulder drop
spinal accessory nerve innervates your trapezius!
what are the deep muscles of the anterior neck? what are they innervated by?
- rectus capitis anterior
- rectus capitis lateralis
- longus capitis
- longus colli
they are generally flexors of the head and neck
they are supplied by motor nerves from the roots of the cervical and brachial plexuses
what are the deep muscles of the lateral neck? what are they innervated by?
- anterior scalene
- middle scalene
- posterior scalene
they are innervated by branches from the ventral rami of the cervical and brachial plexuses
what is the action of the deep muscles of the lateral neck?
flexor and lateral bending of the neck
they’re also accessory muscles of inspiration
what is the root of the neck?
the lower area of the neck sitting on the superior thoracic aperture and apex of the axilla
it contains structures passing from the thorax to the neck and from the neck to the thorax
it also contains structure passing from the thorax and the neck to the upper limb and from the upper limb to the thorax.
in what location would you perform a brachial plexus nerve block?
the needle is inserted in the lower lateral part of the posterior triangle
what is thoracic outlet syndrome?
hypertrophy of the scalene muscles could compress the subclavian artery
what is horner syndrome?
invasion of the stellate ganglion by Pancoast tumor
the tumor will effect the sympathetic fibers as they exit the cord at T1 and ascend to the superior cervical ganglion will produce Horner’s syndrome
what should you worried about with a medial clavicle fracture?
you could puncture the subclavian vein causing an air embolism
where does the subclavian artery begin and end?
it originates from the arch of aorta on the left side and from brachiocephalic artery on the right side
it then ends at the outer border of the first rib by becoming axillary artery
what is the demarkation for the divisions of the subclavian artery?
first part = medial to the anterior scalene
second part = deep to the anterior scalene
third part = between the lateral border of the anterior scalene and the outer border of the first rib
what arises from the 1st division of the subclavian artery?
- vertebral artery
- internal thoracic
- thyrocervical
branches into suprascaular, transverse cervical and inferior thyroid
what arises from the 2nd division of the subclavian artery?
costocervical trunk
what arises from the 3rd division of the subclavian artery?
dorsal scapular
What happens in the narrowing, stenosis, or blockage of subclavian artery at the three divisions 1-3 on the blood supply of the upper limb?
there’s collateral circulation between the 1st and 3rd division!
so if you compress distal to the thyrocervical trunk in the first division it’s okay because the transverse cervical artery will anastomoses with the dorsal scapular
what is subclavian steal syndrome?
Subclavian steal syndrome is a rare condition causing syncope or neurological deficits when the blood supply to the affected arm is increased through exercise
this happens secondary to a proximal stenosing lesion or occlusion in the subclavian artery, typically on the left
so your upper limb is stealing blood from the brain!
where does the subclavian vein start and end?
it starts at the outer border of the first rib as a continuation of the axillary vein
it ends behind the sternoclavicular joint by joining the internal jugular vein to form brachiocephalic vein
the external jugular vein also drains into the subclavian vein
describe the thyroid gland
the thyroid gland is located in the lower part of the neck and is made of two conical lobes connected by narrow isthmus in the midline
the apex of each lobe is level with oblique line of thyroid cartilage which is level with C5
the base of the lobe is level with 4th or 5Th tracheal ring which is about T1
the Isthmus crosses anterior to the 2nd and 3rd tracheal rings –> may need to be divided during tracheostomy
what fascia covers the thyroid gland?
pretracheal fascia
it forms a capsule around the gland
it is attached superiorly to the thyroid cartilage of the larynx and the moves up and down with larynx and hyoid bone during swallowing –> this movement of the gland during swallowing has differential diagnostic value to differentiate thyroid lump from extra-thyroid lump
how do surgeons access the thyroid?
the infra hyoid muscles cover the hyoid!
these muscles need to be retracted laterally or even divided to expose the thyroid gland during thyroidectomy
what is the posterior border of the thyroid gland?
the posteromedial surface is molded around the larynx and pharynx superiorly, and around the trachea and esophagus inferiorly
which nerves run next to the thyroid?
- the external laryngeal nerve runs between the thyroid gland and larynx
- the recurrent laryngeal nerve runs between the thyroid and the esophagus and trachea
the close relation of the external and recurrent laryngeal nerves to the thyroid gland are at risk during thyroidectomy, goiter or thyroid malignancies.
similarly, close relation of the esophagus, trachea, larynx and pharynx makes them susceptible to pressure symptoms during enlargement of thyroid or thyroid or thyroid malignancy
which arteries supply the thyroid gland?
- superior thyroid artery (branch of the external carotid)
- inferior thyroid artery (branch of the thryocervical trunk)
- tiroidea ima artery ((branch of the arch of aorta or brachiocephalic trunk)
what is the venous drainage of the thyroid gland?
the superior and middle thyroid veins drains into the internal jugular vein
the inferior thyroid vein drains into left brachiocephalic vein
which structures are at risk during a thyroidectomy?
the superior and inferior thyroid arteries are crossed by external and recurrent laryngeal nerves, respectively
both nerves are at risk during ligation of these vessels during thyroidectomy
which vessel associated with the thyroid gland could be damaged during a tracheostomy?
the thyroidea ima artery and inferior laryngeal veins are in the midline and may cause bleeding during tracheostomy
what is the parathyroid gland?
4 small lentiform masses 50 mg each that are located on the posterior border of the thyroid gland
it secretes parathyroid hormone which is essential for calcium homeostasis and essential for life
blood supply is mostly derived from the inferior thyroid artery
why would a physician opt to do a partial thyroidectomy rather than a full?
during partial thyroidectomy the posterior part of the gland is preserved to preserve the parathyroid glands
accidental removal of parathyroid gland during thyroidectomy causes hypocalcemia and calcium therapy is needed
what are the 3 cervical fascia?
- prevertebral fascia
- alar fascia
- pretracheal fascia
what is the alar space? what is a potential complication involving it?
the space between alar fascia and prevertebral fascia
it extends into the thorax in the posterior mediastinum to the diaphragm
an infection in the pharynx extending into the retro pharyngeal space, may extend to the alar space which could then reach down to the posterior mediastinum causing mediastinitis –> if not promptly and aggressively treated may result in death
which vein of the following may cause bleeding during tracheostomy?
A, External Jugular vein
B. Internal jugular vein
C. Jugular arch
D. Superior thyroid vein
C. Jugular arch
which nerve of the following is at risk during ligation of superior thyroid artery during thyroidectomy?
A, Vagus nerve
B. Superior laryngeal nerve
C. External laryngeal nerve
D. Internal laryngeal nerve
E. Recurrent laryngeal nerve
C. External laryngeal nerve
thyroid tumor on the medial surface, near the base of the right thyroid lobe may compress which of the following structure?
A.Larynx
B. Pharynx
C. Common carotid artery
D. Vagus nerve
E. Esophagus
E. Esophagus
depression of the hyoid bone can be achieved by the contraction of which muscle of the following?
A. Digastric
B. Sternohyoid
C. Mylohyoid
D. Stylohyoid
E. Geniohyoid
B. Sternohyoid
while driving, you need to make a lane changes into the right lane so you glance over the top of your right shoulder to make sure, the lane is clear and it is safe to change the lane. Which muscle of the following is contracting while looking over your right shoulder?
A. Left sternothyroid
B. Left omohyoid
C. Right sternohyoid
D. Left sternocleidomastoid
E. Right digastric
D. Left sternocleidomastoid
which vessel of the following may be injured during tracheostomy and cause bleeding?
A. Common carotid artery
B. Internal jugular vein
C. Thyroidea ima artery
D. External jugular vein
E. Retromandibular vein
C. Thyroidea ima artery
which muscle of the following elevates the hyoid bone during swallowing?
A. Sternothyroid
B. Sternohyoid
C. Thyrohyoid
D. Mylohyoid
E. Omohyoid
D. Mylohyoid
to stop bleeding from axillary artery from stab wound in the axilla, you press the subclavian artery against which of the following structure?
A, Anterior scalene
B. Middle scalene
C. First rib
D. Middle third of the clavicle
E. Sternoclavicular joint
C. First rib
During partial thyroidectomy which part of the gland should be preserved?
A. Medial surface
B. Apex of the lobe
C. Base of the thyroid lobe
D. Isthmus of thyroid gland
E. Posterior border of the gland
E. Posterior border of the gland
Which of the following bony landmark is used to count thoracic vertebra?
A. Spine of the scapula
B. Spine of C6
C. Spine of C7
D. Spine of T1
E. Transverse process of C7
D. Spine of C7
Which vein of the following may cause bleeding during tracheostomy?
A. Inferior thyroid vein
B. External Jugular vein
C. Internal jugular vein
D. Superior thyroid vein
A. Inferior thyroid vein
